void main() {
  var name = '悟空';
  var age = 18;
  print(name);
  print(age);
  name = '八戒';
  age = 22;
  print(name);
  print(age);
  var num1 = 100;
  var num2 = 200;
  final num4 = num1 + num2;
  const num3 = 300;
  print(num3);
  print(num4);
}
